The Mouse Form serves as the first transformation in Banjo-Kazooie Grunty’s Revenge, the third installment in the series released for Game Boy Advance. It becomes accessible after defeating Klungo in Cliff Farm during the first boss encounter, which rewards players with a Mumbo Token that must be presented to Mumbo Jumbo at his Pad. The Mouse transformation provides significantly increased movement speed compared to Banjo’s standard form and enables access to confined spaces such as mouse holes that would otherwise remain inaccessible. Players activate the transformation’s gnawing technique using the B button, specifically designed for chewing through ropes and chains that block progression. The Mouse Form proves essential for multiple critical objectives across different worlds within the game. In Breegull Beach, it allows players to access Quarry Heights, where six chained Breegulls await rescue, yielding a Jiggy upon freeing all of them from their bonds. Within Spiller’s Harbor, the transformation grants access to Castoffs Castle located in Bilge Haven, which contains a complex maze featuring switch puzzles that require the Mouse’s small size to navigate. The sandcastle maze within this area presents a two-floor structure where players must activate four levers by gnawing them to spawn bridges on the second floor, leading to a Jiggy and some Musical Notes. In Freezing Furnace, the Mouse can enter a block of ice positioned near Mumbo’s Skull, revealing additional collectibles hidden within. Additionally, within Cliff Farm itself, the Mouse Form enables access to Bluff Barn’s rafters and Crag Mill’s elevator system by chewing through rope mechanisms. However, the transformation carries some limitations as it represents the only form in the game completely unable to inflict damage, requiring players to avoid combat entirely while transformed. Furthermore, contact with any water source immediately causes Banjo and Kazooie to lose all Honeycomb health, effectively killing them instantly due to the Mouse’s vulnerability to liquid environments.
